ICCs are cells found in the myenteric plexus and nearby areas between the circular and longitudinal layers of the gastrointestinal tract. Their function is to regulate gastrointestinal motility, or peristalsis, which is the autonomic movement of the GI tract to propel food through the system. The ICCs initiate and propagate the slow wave activity of gastrointestinal wall muscles. Either ICCs, or the more primitive cells that give rise to ICCs, are the source of gastrointestinal stromal tumors.